You're overthinking it way too much.
Was first thing that popped in my head. What is the grunts that will fill up 99% of the bad guys in a level that do nothing. Thinking of the Final Fantasy games its some random soldier with an automatic gun of some sort, usually a rifle of some sort. And that just feels stupid having 100's of guys with automatic rifles just standing there while your running around slashing them with your oversized sword.
That's why Zelda was fine, casue you have enemies with clubs or swords. Or Fire Emblem would be great, cause again old fashioned weapons.
Throwing in guns feel slike it would make me lose what little immersion the games offer. Yea warrior gamesmake you feel like your a god by killing hundreds in seconds, but at least with primitive weapons you sort of a have that illusion that they aren't just decorations that don't really ever attack you but instead you are just way better with a sword than them, or whatever weapon you have.